#include "tlv.h"
const unsigned short crc_itu_t_table[256] = {
        0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7,
        0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef,
        0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6,
        0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de,
        0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485,
        0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d,
        0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4,
        0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc,
        0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823,
        0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b,
        0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12,
        0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a,
        0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41,
        0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49,
        0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70,
        0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78,
        0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f,
        0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067,
        0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e,
        0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256,
        0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d,
        0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
        0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c,
        0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634,
        0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab,
        0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3,
        0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a,
        0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92,
        0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9,
        0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1,
        0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8,
        0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0
};

/**
 * crc_itu_t - Compute the CRC-ITU-T for the data buffer
 *
 * @crc:     previous CRC value
 * @buffer:  data pointer
 * @len:     number of bytes in the buffer
 *
 * Returns the updated CRC value
 */
unsigned short crc_itu_t(unsigned short crc, const unsigned char *buffer, unsigned int len)
{
        while (len--)
                crc = crc_itu_t_byte(crc, *buffer++);
        return crc;
}

int ushort_to_bytes(unsigned char *bytes, unsigned short val)
{
    int              size  = sizeof (unsigned short);
    int              i = 0;

    if( !bytes )
        return 0;

    while (size)
    {
        *(bytes + --size) = (val >> ((8 * i++) & 0xFF));
    }

    return sizeof(unsigned short);
}

unsigned short bytes_to_ushort(unsigned char *bytes, int len)
{
    int            i = 0;
    unsigned short val = 0;

    if( !bytes || len > sizeof(unsigned short) )
        return 0;

    for(i=0; i<len; i++)
    {
        val += bytes[i];

        if (i < len - 1)
            val = val << 8;
    }

    return val;
}

/* 树莓派上获取温度30.5C报文
 * H                  T            L              Value           CRC1    CRC2
 * 0xFD              0x03         0x00         0x14 0x3A           0x12    0x34
*/

int  pack_temp(char *buf, int size)
{
    unsigned short crc16=0;
    int     pack_len = 0;
    int     data_len = 0;
    int     ofset = 0;
    float   temp=28.75;
    int     i,j;

    if(!buf || size < TLV_MINI_SIZE)
    {
        printf("Invalid input adgument\n");
        return 0;
    }
    buf[ofset]=HEAD;//报文头
    ofset +=1;

    buf[ofset]=TAG_TEMP;//TAG
    ofset +=1;

    DS18B20_SampleData(&temp);//获取实时温度值
    i=(int)temp; //整数部分
    j=(int) ((temp-i) *100);//小数部分

    data_len = 2;
	pack_len= data_len + TLV_FIXED_SIZE;//总长度为数据长度加上额外固定长度5

	buf[ofset]=pack_len;
    ofset +=1;

    buf[ofset]=i;
    ofset+=1;

    buf[ofset]=j;
    ofset+=1;

    crc16=crc_itu_t(MAGIC_CRC, buf, ofset);
    ushort_to_bytes(&buf[ofset], crc16);
    ofset +=2;
    return ofset;//返回索引值
}

void dump_buf(char *type, char *data, int len)//data指针，指向buf的首地址，len是buf的长度
{
    if(type)
    {
        printf("%s:\n", type);
    }

    int i;
    for(i=0; i<len; i++)
    {
        printf("0x%02x\n",data[i]);
    }
    printf("\n");

}

int unpack(char *buf,int bytes)
{
      int                 i;
      char                *ptr=NULL;
      int                 len;
      unsigned short      crc,val;

   // float                 t=0.0;
      float                 n,m;
      float                  temp;

      if( !buf )
      {
          printf("Invailed input!\n");
          return 0;
      }
        printf("sizeof(buf):%d\n",sizeof(buf));

//again:
     if( bytes<TLV_MINI_SIZE )   //数据长度太短
     {
         printf("buf 不完整\n");
         return bytes;
     }
    printf("buf is good!\n");

    for(i=0;i<bytes;i++)
    {
          if( (unsigned char)buf[i]==HEAD )
          {
              if( bytes-i<2 )
              {
                  printf("can not find length...\n");  //剩下的数据不能读到tlv的长度
                  memmove(buf,&buf[i],bytes-i);
                  return bytes-i;
               }

               ptr=&buf[i];
               len=ptr[2];
               printf("tlv length:%d\n",len);

               if(len < TLV_MINI_SIZE||len>BUF_SIZE )  //这一帧中（length）长度错误
               {
                  memmove(buf, &ptr[2], bytes-i-2) ;
                  bytes = bytes -i -2 ;
                 // goto again;
               }
               printf("tlv_len is ture!\n");

               if(len < bytes - i)//如果tlv长度比剩下的数据长度还长
               {
                   printf("bytes-i:%d\n",bytes-i);
                   printf("Error!\n");
                   memmove(buf, ptr, bytes-i) ;
                   return bytes - i ;
               }

               crc = crc_itu_t(MAGIC_CRC,(unsigned char*)ptr, len-2);
               val = bytes_to_ushort((unsigned char*)&ptr[len-2],2) ;
               if( val!=crc ) // crc检验出错！
              {
                    printf("crc is not ture!\n");
                    memmove(buf, &ptr[len], bytes-i-len) ;
                    bytes = bytes -i -len ;
                    //goto again ;
               }

               m=ptr[3];
               n=((float)ptr[4])/100;
               temp= m+n;
               printf("Temperature is:%.2f\n",temp);

               memmove(buf,&ptr[len], bytes-i-len) ;//处理完正确的一帧之后将其移出数组
               bytes = bytes -i -len ;
            //   goto again ;
       }
   }
   return 0;
}

